Seems to be a problem where the boat with or without entities dissapears when you get out of it (via spacebar or shift, doesn't matter). The entitie can "be there", so the boat, but not "physically". I used to think I lost boats, but it seems that they return to the first place where you put it on water. If I retrace to the origin and go back to the end of the boat travel, it reappears.

Steps to Reproduce:

1.1.- Put a boat in the water (a.k.a. "origin").

1.2.- Travel 1500 blocks or so, just be sure that the origin is unrendered.

1.3.- Get out of the boat (this will be "end").

1.4.- The boat will "dissapear".

1.5.- Go back to origin. (in boat if you want, so you can skip step 2){}

1.6.- Go back to end.

1.7.- The boat will "reappear".

2.1.- Place a boat in the water.

2.2.- Travel a rendered or unredered distance (100 or 1500 blocks)  without leaving the boat.{}

2.3.- Go back to origin (at least the same chunk).{}

2.4.- Leave the boat (via spacebar or shift)

Expected results:

1A.- The boat "dissapears" if the origin is different than the end and also if it the origin has been unrendered at the moment of disembarking (as seen in "first boat" video).

1B.- The boat "reappears" if the player travels to origin and goes back to end by retracing the path (as seen in the "retraced boat "video)

2.- When origin and end are both rendered (if it's the same chunk or not), the boat moves to origin and goes back to end at the moment of disembarking in a very fast move, even if the whole path is not rendered.